440 PROTOZOOLOGY 



number of striae become visible during movement, showing there 

 is a very thin pellicle; endoplasm always vacuolated, the vacuoles 

 varying in size (up to 30m in diameter); vesicular nucleus with an 

 endosome; 50-125/1 long during locomotion; fresh water. 



A. vespertilio Penard (Fig. 185, b, c.) Pseudo podia conical, com- 

 paratively short, connected at base by web-like expansions of ecto- 

 plasm; endoplasm colorless, with numerous granules and food par- 

 ticles; a single vesicular nucleus with a large endosome; contractile 

 vacuoles; 60-100/x long; fresh water. Cannibalism (Lapage, 1922); 

 contractile vacuole (Hyman, 1936) ; morphology and biology (Raabe, 

 1951). 



A. gorgonia P. (Fig. 185, d-f). Body globular when inactive with 

 a variable number of radiating "arms," formed on all sides; when 

 in locomotion, clavate; nucleus vesicular, with a large endosome; 

 rounded forms 40-50m in diameter; clavate individuals up to 100m; 

 fresh water among vegetation. 



A. radiosa Ehrenberg (Fig. 185, g). Small, usually inactive; 

 globular or oval in outline; with 3-10 radiating slender pseudo podia 

 which vary in length and degree of rigidity; when pseudo pods are 

 withdrawn, the organism may be similar to A. proieus in general ap- 

 pearance; pseudo pods straight, curved or spirally coiled; size varies, 

 usually about 30m in diameter, up to 120m or more: fresh water. 



Genus Dinamoeba Leidy. Essentially Amoeba, but the temporary 

 posterior region of body with retractile papillae ; body surface includ- 

 ing pseudopods and papillae, bristling with minute spicules or mo- 

 tionless cils; often surrounded by a thick layer of delicate hyaline 

 jelly, even during locomotion; fresh water. 



D. mirabilis L. (Fig. 185, h). Oval to limaciform; spheroid when 

 floating; pseudo podia numerous, conical; ectoplasm clear, usually 

 with cils; endoplasm with food vacuoles, oil (?) spherules and large 

 clear globules; nucleus and contractile vacuole obscure; spherical 

 forms 64-160m in diameter; creeping forms 152-340/x by 60-220m; 

 cyst about 160m in diameter (Groot, 1936); in sphagnous swamp. 



Genus Pelomyxa Greeff. Large amoeboid organisms, ranging from 

 0.5 to 4 or 5 mm. in length when clavate and moving progressively; 

 nuclei numerous, less than 100 to 1000 or more; many small contrac- 

 tile vacuoles; refringent bodies ("Glanzkorper") of various dimen- 

 sion and number; with or without bacterial inclusions (which Penard 

 and others consider as symbiotic); holozoic on plant or animal or- 

 ganisms or detritus; plasmotomy simple or multiple; in fresh water. 

 Several species (Kudo, 1946). Nomenclature (Schaeffer, 1926; Mast 

 and Johnson, 1931; Rice, 1945; Kudo, 1946, 1952; Wilber, 1947). 



